Two US army helicopter pilots talk on top of their Blackhawk helicopter at Kandahar airbase on March 20, 2011

Two US army helicopter pilots talk on top of their Blackhawk helicopter at Kandahar airbase, southern Afghanistan on March 20, 2011. A freak hailstorm in Afghanistan damaged more than 80 US military helicopters, wrecking rotor blades, shattering windows and grounding aircraft for weeks until repairs were completed, the army said on Thursday.